1. Field of the Invention
The present invention generally relates to a reproduction method, a program, a recording medium, and a drive apparatus, and especially relates to a reproduction method for reproducing information recorded on an information recording medium, a computer-executable program and the information recording medium for storing the program, and a drive apparatus for carrying out at least reproduction of contents of the information recording medium, which drive apparatus does not have to be, but may also be capable of recording and erasing contents of the information recording medium.
2. Description of the Related Art
With advancements of personal computers (PCs), it has become possible to deal with AV (Audio-Visual) information, such as music and images. Since the amount of the AV information is very large, optical disks, such as a CD (compact disk), and a DVD (digital versatile disk) capable of recording data of about 7 times as much as the CD on a disk of the same diameter as the CD, come to attract attention as an information recording medium. With the prices of CDs and DVDs having dropped, optical disk apparatuses capable of handling CDs and DVDs have come to spread. Here, as an optical disk of the CD system, CD-ROM, CD-R (CD-recordable), CD-RW (CD-rewritable), etc., are marketed; and as for the DVD system, DVD-ROM, DVD-RAM, DVD-R (DVD-recordable), DVD-RW (DVD-rewritable), DVD+R (DVD+recordable), DVD+RW (DVD+rewritable), etc., are marketed.
As for the recordable disks, such as CD-R, DVD+R, etc., a recording zone, in which data are recorded, is divided into tracks (“fragments” in the case of DVD+R) such that the data are recorded on each track. This method is called multi-track recording. In the following, for convenience, both tracks and fragments are generically called tracks.
For example, in a DVD+R, up to 16 tracks can be set up as a session. In a zone called the lead-in zone (LIZ), a block called the session disk control block (SDCB) is provided that stores information about the tracks included in a session, such as track numbers, starting addresses of the tracks, ending addresses of the tracks, etc., the information being called track information. Usually, the track information recorded on the SDCB is read when the DVD+R is loaded (mounted) to a predetermined position of an optical disk apparatus, and the track information is held in a memory such that the track information can be referred to when required. In the case of DVD+R, up to 191 sessions can be present on the disk. When there are two or more sessions, the track information of the second session and all the subsequent sessions is recorded in SDCBs that are provided in a zone called “intro” of each of the sessions other than the first session.
Further, in DVD+R, multiple pieces of data can be recorded in a track one by one at different times so that files having a comparatively small amount of data can be recorded on the track. Accordingly, a state of the track is generally one of being fully recorded, being totally vacant, and having a recorded zone where data are recorded and a non-recorded zone where there are no data recorded. A track having a recorded zone and a non-recorded zone is called a partially recorded track. Generally, data have to be continuously recorded in a track from the starting address of the track. For this reason, it is necessary to determine the boundary position between the recorded zone and the non-recorded zone of the track, when adding data to a partially recorded track. The address that represents the boundary position is called the next writable address (NWA). Although the starting address and the ending address of a track are recorded in the SDCB as described above, the information about the boundary position between a recorded zone and a non-recorded zone, for example, NWA, is not recorded anywhere. Therefore, when adding data to a partially recorded track, NWA has to be detected each time recording is to be carried out.
In the case of CD-R, although the greatest number of sessions is not prescribed, the greatest number of tracks on a disk is limited to 99. The track information of each track is recorded in a zone called the program memory area (PMA) that is provided in the innermost circumference zone of the CD-R. Like the SDCB in DVD+R as mentioned above, the information recorded on PMA is usually read when the CD-R is loaded or mounted, is held in a memory, and is referred to as required.
According to a recording method called “packet-writing” for CD-R, it is possible that multiple pieces of data are recorded in a track one by one at different times. Accordingly, a partially recorded track can be present in CD-R. In the packet-writing recording method, data also have to be continuously recorded in a track from the starting address of the track. For this reason, it is necessary to determine the boundary position (for example, NWA) between a recorded zone and a non-recorded zone of the track, when adding data to the partially recorded track. Again, here in CD-R, the information about the boundary position between the recorded zone and the non-recorded zone is not provided in the disk, and NWA has to be detected each time data are to be added to the partially recorded track.
Conventionally, NWA of a track concerned (target track) of DVD+R and CD-R is detected by searching for the boundary position that divides the recorded zone and the non-recorded zone by sequentially scanning from the starting address toward the ending address of the target track, or by the so-called binary search by which a zone where NWA is expectedly to be contained is sequentially narrowed down. However, according to these detection methods, a problem is that detection time becomes long as the capacity of the target track is increased.
To cope with the problem, various apparatuses for shortening the detection time of NWA have been proposed (for example, patent reference 1 and patent reference 2).
[Patent reference 1]
JP,11-120573, A
[Patent reference 2]
JP,7-326158, A